Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

Autor: Arie Kalir, Alexandra Poljakoff-Mayber, Gila Omri
Rok vydání: 1984
Předmět:
Zdroj: Physiologia Plantarum. 62:238-244
ISSN: 1399-3054
0031-9317
DOI: 10.1111/j.1399-3054.1984.tb00377.x
Popis: The effect of high NaCl concentrations on the activity of catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7) and malate dehydrogenase (NAD+-linked; EC 1.1.1.37) from leaves of Halimione portulacoides (L.) Aellen was studied. The plants were exposed to high salinity during growth and enzyme activity was measured either in the absence or in the presence of various concentrations of NaCl. Increasing salinity in vitro induced three types of effects: (1) an increase in activity (peroxidase); (2) a decrease in activity (catalase); (3) stimulation by low salt concentration but inhibition by higher concentrations (malate dehydrogenase). Salinity in vivo induced a marked decrease in catalase and malate dehydrogenase activities. However, peroxidase in vivo showed an optimum curve of activity vs external NaCl concentration, with an optimum at ca 1 M NaCl. Exposure of plants to salinity induced changes in the properties of the enzyme proteins: they precipitated at a higher (NH4)2SO4 concentration, were eluted later during Sephadex G-200 filtration, and showed a shift in the maximal, minimal and optimal temperatures. These data are interpreted as evidence for conformational changes in the enzymes due to prolonged exposure to high salinity stress; such changes could be disruption into monomers (catalase and malate dehydrogenase), or changes in molecular shape (in the peroxidase).
Databáze: OpenAIRE
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